Within the self-service vending machine industry, many machines exist to prepare heated mixtures. Often, repetitive preparation of multiple, varied beverages and soups occurs using a single serve package from the same machine. Each single serve package is typically in the form of a capsule that contains a measured amount of a dry substance. One such capsule is shown by Denisart et al. within International Publication Number WO 03/059778 A2 published on Jul. 24, 2003.
When a liquid, typically hot water, is introduced to contents of a capsule, a food liquid such as a beverage or soup is thus formed. Different food liquids have different requirements to produce the best drinking experience depending upon the given food liquid. Such requirements include crema/foam volume, texture, and the in-cup temperature. Further, the in-cup temperature is related to the foam volume and texture.
Existing liquid heating technology used often in such self-service vending machines is typically only able to deliver hot liquid at one fixed temperature for all products. Most commonly, the heated liquid is water drawn from a public water main with or without filtration, but may also include water drawn from a private source such as a well or compact water tank. Heating water to a fixed temperature for all products limits the possibility to prepare different beverages each with the best quality. In addition, such self-service vending machines cool down during idle periods. Accordingly, the first dispensing of beverage prepared after a machine has been idle for a period of time would deliver beverages with a significant lower in-cup temperature due to the heat lost to the mixing device itself, or alternatively, the machine would require a significant warm-up time in order for the water to reach the desired in-cup temperature.
On-demand or instant heaters are known for the use in beverage systems. Such on-demand or instant heaters are generally defined as heating assemblies that are able to provide an accurate water temperature without requiring a pre-warming time. Such heaters generally include a series of heating components, such as electrical resistors or heating cartridges (e.g., Calrods®), where an initial heating component is controlled to heat the water within a preset temperature range lower than the final preset temperature desired and a second heating component is controlled to adjust, or fine tune, the water to a final preset temperature from the first preset temperature. There exists other sorts of instant heaters which are not based on Calrods® or ceramic insulated type heating elements, but rather on thick film technology. Such heaters may be formed by a hollow annular member with thick film type resistors printed thereon as shown by U.S. Pat. No. 6,459,854 issued to Yoakim et al. on Oct. 1, 2002 or as shown by Boussemart et al. within International Publication Number WO 2004/006742 published Jan. 22, 2004.
It would accordingly be desirable to provide a system for dispensing food liquids that overcomes difficulties associated with existing self-service vending machines. It is, therefore, desirable to provide an improved beverage dispensing system that would benefit from incorporation of an on-demand heater that is able to deliver hot liquid/water at any temperature and ideally vary such temperature dynamically. What would be needed is an improved beverage dispensing system optimized for delivering improved crema/foam and in-cup temperature, in terms of efficient dissolution of the powder/liquid, creation of foam inside the capsule, and compensation for the heat loss during the beverage flowing into the cup.